Linux Practical Security Course

Dear Members ,
I am happy to announce that Linux Practical Security by LZH Project is complete. We will launch it shortly. Please support us by buying and rating this course. For first 20 buyers there will be a discount of $5. Total cost is $25. You can also book your copy by sending me email to Please take a look at the introductory video here:

Openstack dashboard gives error “Error: Unable to retrieve information”

So today i ran into one more issue with Openstack , the error showed up  when i logged in to the dashboard and clicked on Project–>Instances.

What i saw terrified me because is saw “NOTHING” !

A day before i had the same issue and i thought it’s related to RAM so i restarted and everything started and operated normally, but this time the reboot didn’t help.

So i started scratching my head and started wondering what might be the reason. I searched internet but no success. I searched log files but nothing made sense at that time, so i rebooted one more time and an Error appeared saying something like “Openstack glance-registry api error limit reached ” So that gave me a head start that it has something to do with system being low in space.

A df -h showed that / is 100% full. I removed some unnecessary files , rebooted the system and Viola !

All started to work Normally.


Make Sure you have enough space with OpenStack


Unable to Connect “The Squid Error “

So today i had a strange problem when i was only able to access and not other sites. I was able to browse gmail, but not mail ru. Everything was working fine but out of no where this error “Unable to Connect” appeared on my Browsers. It was kinda strange, since i made no changes to my system” Also i was not sure if it’s the system or the Gateway.
Observation on System:
1) Both Firefox and Chrome giving the same problem.
2) I was able to browse with Chrome if Ultrasuf Extension was enabled.
3) Firebug reported “Aborted” in the Net tab

Steps taken:

Restarted the System
Changed the IP address
System Not Fixed Continue reading

Solving Call Drop Issue in Elastix / Asterisk

If you change your Network and you find that the working Elastix / Asterisk box is now dropping calls every 15 to 25 secs.  One of the most probable reason is “NAT” .

The solution which worked for me is changing the sip_custom.conf found in /etc/asterisk/ directory.

Open it with your favorite editor such as vim or nano and add the following lines.

externip=  < Your External Ip with Subnet Here >
localnet= < Your Internal Ip with Subnet Here >

Hope this will help someone.


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Bash script: Search for text in a web app

I started taking small steps into bash scripting with this little tool that help me find a lot of useful stuff in Vtiger, but it can be applyed to anything else with some little mods. This script finds files in Vtiger installation that contain the text requested. It is reporting on the file name and path and also highligsts the line than contains the text. So here is the script. Breakdown is below Continue reading

Missing panel in Ubuntu Mate?

So something went wrong and your panel does no longer appear even after the restart. Here is what you can do after you pulled all the hair.

  • Open your terminal window by clicking the desktop and choosing Open in Terminal
  • Type
    mate-panel --reset

    and press Enter

That should do it, But what if it doesn’t?

  • Open terminal again and type

    and press Enter

  • Go to Look And Feel tab on the left and chose Tweak on the right
  • Find where panel settings reside and chose any look of panel that you like and tweak some settings

It has not solved too much for me because the bottom panels were not showing no matter what, but at least I could work and search for the further fixes.